1. Field of the Invention
This invention relates to ophthalmoscopes for allowing physicians to view the retina of a patient's eye.
2. Description of the Prior Art
Applicant is aware of the following U.S. patents: Allen (U.S. Pat. No. 1,116,529); Graff (U.S. Pat. No. 2,195,169); Vannas (U.S. Pat. No. 2,633,122); Kosche et al (U.S. Pat. No. 3,012,462); Keeler (U.S. Pat. No. 3,131,695); Moore et al (U.S. Pat. No. 3,439,978); Speelman (U.S. Pat. No. 3,501,228); Schenk (U.S. Pat. No. 3,586,424); and Matsura (U.S. Pat. No. 3,698,099). None of the above patents disclose or suggest the present invention.
Ophthalmoscopes can be divided into two general types according to their method of use. The first type of ophthalmoscope is illustrated by the Graff patent. In this type, the ophthalmoscope is held a substantial distance away from the patient's eye to be viewed. This spacing of the ophthalmoscope from the eye, among other disadvantages, limits the angle of view. The second type of ophthalmoscope is illustrated by the Vannas patent. In this type, the ophthalmoscope is held against or spaced only slightly from the patient's eye to be viewed. The present invention is of this second type.
One major problem with present ophthalmoscopes is that they are extremely difficult to use. In fact, special courses are typically given ophthalmologists on how to use the ophthalmoscope. Another problem with present ophthalmoscopes is that when used in retina surgery procedures, considerable clouding of the cornea occurs.